In the packaging industry, a variety of devices have been developed to automatically fabricate foam filled bags for use as protective inserts in packages. Some examples of these foam-in-bag fabrication devices can be seen in U.S. Pat. Nos. 5,376,219; 4,854,109; 4,938,007; 5,139,151; 5,575,435; 5,679,208; and 5,727,370.
In addition to the common occurrence of foam dispenser system lock up or poor mix performance in prior art foam-in-bag systems, the film supply, tracking, sealing and feed components of prior art foam-in-bag systems also represent particular sources of headaches for operators of prior art devices. The headaches include, for example, attempting to understand and operate a highly complicated, multiple component assembly for feeding, sealing, tracking and/or supplying film (often C-fold) to the bag formation area; high breakdown or misadjustment occurrence due to the number of components and complex arrangement of the components; high service requirements (also due in part to the number of components and high complexity of the arrangement in the components); poor quality bag formation, often associated with poor tracking performance, particularly with respect to C-fold film supply systems which have a different type of side edge arrangement (unconnected versus connected edge) that is inherently prone to difficult maintenance of good tracking characteristics; vent hole blockage and/or product contamination from foam exiting the vent(s); and lack of versatility in regard to vent length and vent location.
Another particularly problematic area associated with the prior art foam-in-bag systems lies in the area of heated resistance wire replacement, both in regard to edge sealing and in regard to the cross-cutting/sealing systems. In the prior art systems, there is often required delicate operator manipulation with certain tools to achieve removal and reinsertion of broken, or worn, heated wires (which is a common occurrence in the thin heated resistance wires used in the industry to form the seals).
In addition, prior art systems suffer from other drawbacks, such as relatively slow bag formation and a slow throughput of completed bags which, in some systems, is partially due to a reverse feed requirement to break an upper, not-yet-completely formed bag from a completed bag with one or both adhered by the bond formed between the earlier melted and presently cooled plastic material on the heated cross-cut wire.